Green Threshold Intervals focus on increasing the amount of power you can generate aerobically (i.e. increasing your anaerobic threshold). The more power you can produce aerobically, the longer you can sustain it without fatiguing.
So these intervals are aimed at increasing the amount of power you can produce without slowing down.
Focus on maintaining as much speed as you can while staying in the green zone target. As your fitness increases, you can increase the work period.
Goal: Improve your ability to produce power aerobically so you can go longer without fatiguing. Once you cross your anaerobic threshold, more of your energy is produced anaerobically; this leads to fatiguing faster.
How: Get your heart rate to the top of your green zone if you’re standing, or the middle of your green zone if you’re seated. Maintain this level for 3-6 minutes. Actively recover to the middle or top of your blue zone over 2-4 minutes. Repeat for 2-5 reps. Do this method on a day when your recovery is at 90% or higher to get as close to your true anaerobic threshold as possible.
Exercises: Any cardiovascular exercises will work for this method.